MicroElectroMechanical Systems (MEMS) have been developed as alternatives to conventional electromechanical devices, such as relays, actuators, valves and sensors. MEMS devices are potentially low-cost devices, due to the use of microelectronic fabrication techniques. New functionality also may be provided, because MEMS devices can be much smaller than conventional electromechanical devices.
A major breakthrough in MEMS devices is described in U.S. Pat. No. 5,909,078 entitled Thermal Arched Beam Microelectromechanical Actuators to Wood et al. (Wood), the disclosure of which is hereby incorporated herein by reference. Wood discloses a family of thermal arched beam microelectromechanical actuators that include an arched beam which extends between spaced-apart supports on a microelectronic substrate. The arched beam expands upon application of heat thereto. For example, as described in Wood, a current is passed through the arched beams to cause thermal expansion thereof. Alternatively, as described in Wood, the thermal arched beams are heated by an external heater across an air gap.
When used as a microelectromechanical actuator, thermal expansion of the arched beam can create relatively large displacement and relatively large forces while consuming reasonable power. Thermal arched beams can be used to provide actuators, relays, sensors, microvalves and other MEMS devices. Other thermal arched beam microelectromechanical devices and associated fabrication methods are described, for example, in U.S. Pat. No. 5,994,816 to Dhuler et al. entitled Thermal Arched Beam Microelectro-mechanical Devices and Associated Fabrication Methods, the disclosure of which is hereby incorporated herein by reference. Notwithstanding the above, there continues to be a need to further improve MEMS devices.